Porvac® Subunit Vaccine E2-CD154 Induces Remarkable Rapid Protection against Classical Swine Fever Virus

Abstract

Live attenuated C-strain classical swine fever vaccines provide early onset protection. These vaccines confer effective protection against the disease at 5–7 days post-vaccination. It was previously reported that intramuscular administration of the Porvac® vaccine protects against highly virulent classical swine fever virus (CSFV) “Margarita” strain as early as seven days post-vaccination. In order to identify how rapidly protection against CSFV is conferred after a single dose of the Porvac® subunit vaccine E2-CD154, 15 swine, vaccinated with a single dose of Porvac®, were challenged intranasally at five, three, and one day post-vaccination with 2 x 103 LD50 of the highly pathogenic Cuban “Margarita” strain of the classical swine fever virus. Another five animals were the negative control of the experiment. The results provided clinical and virological data confirming protection at five days post-vaccination. Classical swine fever (CSF)-specific IFNγ T cell responses were detected in vaccinated animals but not detected in unvaccinated control animals. These results provided the first data that a subunit protein vaccine demonstrates clinical and viral protection at five days post-vaccination, as modified live vaccines.

Safety and immunogenicity in piglets of two immunization schedules initiated at two or three weeks of age with PorvacÒ, a classical swine fever subunit marker vaccine.

“…Porvac® is a Cuban subunit marker vaccine against CSFV, which is based on a recombinant chimeric antigen comprising the E2 protein of CSFV and the molecular adjuvant CD154. This vaccine has been safe and capable of inducing an unusually rapid onset of protection against a challenge with a highly pathogenic CSFV strain, which is similar to the one described for MLV [9][10][11] . Porvac® induces both high neutralizing antibodies (NAb) titers and cell-mediated immune response and can interfere with the transmission of the virus from pregnant sows to their offspring 12 .…”

Field evaluation of the safety and immunogenicity of a classical swine fever virus E2 subunit vaccine in breeding and nursery animals on Jeju Island, South Korea

“…Recent studies indicated the safety and efficacy of various CSF-E2 subunit protein-based non-infectious marker vaccines on breeding pigs under field or experimental conditions [ 19 20 21 22 ]. Likewise, in trial 1 of this study, high safety and immunity were obtained by the application of Bayovac CSF-E2 vaccine on pregnant sows in field farms.…”

“…The latter relies on antibody detection against the CSFV E rns protein to identify infection with field virus [ 4 ]. Moreover, recent studies exhibited their efficacy on early protection and vertical transmission prevention against CSF infection under experimental or field conditions [ 19 20 21 22 ].…”

Transboundary Animal Diseases, an Overview of 17 Diseases with Potential for Global Spread and Serious Consequences

“…The deletion of glycosylation sites has shown promise for the development of attenuated vaccine strains [181]. One further approach has been production of a fusion protein, combining the E2 protein to the extracellular segment of the host CD154 molecule, which is licensed as Povac ® in Cuba [222,223]. Another fusion protein vaccine combines the E2 protein with the host Fc region of IgG.…”